Photographic foot attachment with retractable hot contact

ABSTRACT

A retractable hot center contact for a foot attachment of a photographic flash light unit having a spring biasing means mounted for movement within the attachment, a first end portion of the spring biasing means is retained against movement by the foot attachment and a second end portion of the spring biasing means extends through and outwardly of an open passageway in the foot attachment to provide a hot center contact. When a plug of a shutter cord is inserted through a passageway in the foot attachment it displaces the spring biasing means and causes its hot center contact end portion to be simultaneously retracted from an exposed dangerous contactable position outside the attachment to a safe noncontactable position inside the passageway.

United States [451 Feb. 4, 1975 PHOTOGRAPHIC FOOT ATTACHMENT WITH RETRACTABLE HOT CONTACT [75] Inventors: David C. Smart, Westminster; Dean M. Peterson, Littleton, both of C010. [73] Assignee: Honeywell Inc., Minneapolis, Minn. [22] Filed: Sept. 20, 1973 [21] Appl. No.: 399,276

[52] US. Cl 354/126, ZOO/51.1, 240/13,

339/31, 339/33, 354/141, 354/145 [51] Int. Cl. G03b 15/05 [58] Field of Search 95/11 L, 11 R, 11.5 R,

95/86; 240/13; ZOO/51.1, 51.09, 52; 339/31, 33; 354/126, 141, 145

Primary Examiner-Samuel S. Matthews Assistant Examinerl(enneth C. Hutchison Attorney, Agent, or Firm-Arthur H. Swanson; Lockwood D. Burton; John Shaw Stevenson [57] ABSTRACT A retractable hot center contact for a foot attachment of a photographic flash light unit having a spring biasing means mounted for movement within the attachment, a first end portion of the spring biasing means is retained against movement by the foot attachment and a second end portion of the spring biasing means extends through and outwardly of an open passageway in the foot attachment to provide a hot center contact. When a plug of a shutter cord is inserted through a passageway in the foot attachment it displaces the spring biasing means and causes its hot center contact end portion to be simultaneously retracted from an exposed dangerous contactable position outside the attachment to a safe noncontactable position inside the passageway.

3 Claims, 3 Drawing Figures 1 PI-IOTOGRAPI-IIC FOOT ATTACHMENT WITH RETRACTABLE HOT CONTACT CROSS REFERENCE TO RELATED APPLICATION Subject matter shown and described but not claimed herein is shown, described and claimed in a copending application of David C. Smart filed Ser. No. 399,200 filed in Sept. 20, 1973.

BACKGROUND OF THE INVENTION 1. Field ofthe Invention The present invention relates to an improved foot attachment of the type generally classified in the U.S. Pat. Office with article support attaching means (class 248-187).

2. Description of the Prior Art Prior art photographic accessories, for example, photographic flash lights have heretofore employed foot attachments to slidably mount these accessories on shoe receptacles that are fixedly mounted on cameras and the-like to which the accessory is to be attached. Examples of such foot attachments are shown in the A. R. Schnase U.S. Pat. No. 3,356,325, the Wallace A. Monson Design U.S. Pat. No.D2l4,214 and the Alwin .I. Stahel ll Design U.S. Pat. No. D2l4,764.

It has heretofore been the practice with prior art devices of the aforementioned type to provide means to lock the foot in a desired non-movable position on shoe receptacles in order, for example, to maintain the direction of light emitted from a flash light supported by the shoe at a fixed angle. Use of locking means was necessary because too loose a manufacturing tolerance often times exist between the foot and the shoe. The prior art locking means that is employed in the aforementioned A. R. Schnase patent is a rotatable cam, in the Monson patent it is a screw knob and in the Stahel II patent it is a lever.

SUMMARY OF THE INVENTION An object of the present invention is to provide a construction for a foot attachment which when slidably mounted in an associated shoe receptacle will be held in a desired firm, non-movable, aligned relationship with, for example, the camera to which the receptacle is attached and which will not require the use of locks such as has heretofore been required by the previously mentioned foot attaching devices.

It is another object of the invention to providea universal foot attachment of the aforementioned type which can be mounted on all camera shoes now in use even though the sides of the foot attachments or its corresponding shoe receptacle exceeds certain desired specified manufacturing tolerances.

It is another object to provide a leaf spring for the foot that will allow a side of the foot to be pressed into good frictional contact with the shoe receptacle when such a foot is mounted thereon.

It is another object to provide a foot attachment that is economical to manufacture and which can be readily slidably mounted on and removed from an associated shoe receptacle.

In accordance with the invention there is provided within the foot a torsional spring having a coiled spring portion and a hot center contact portion. The latter is adapted to be moved outwardly of the foot through an open passageway and is retractable from an exposed and potentially dangerous position outside the passageway to a safe non-contactable position inside the passageway. The retraction is brought about by the displacement of said coiled spring portion when the plug of a shutter cord is brought into contact with said coil spring portion. The improved foot of this invention, therefore, is adapted for use with a conventional shoe and also for a so-called "hot shoe.

In accomplishing these and other objects there has been provided, in accordance with the present invention, a foot made of a high frictional material such as polyurethane which is commercially identifiable under the trade name of TEXIN E902. The foot is formed with an internal cavity therein. A substantially bow shaped leaf spring is positioned to apply forces against opposite inner walls of the cavity that are adjacent to two opposing mounting side wall portions of the foot. One arcuate portion of this leaf spring is positioned to extend in an opening in one of the side wall portions of the body. As the extending arcuate spring portion is partially pushed into the housing by an associated side portion of a shoe receptacle the spring transfers the compressing force introduced by the aforementioned movement of the shoe receptacle to an opposite inner wall of the cavity that is adjacent an associated side wall of the foot. As the sides of the foot are slidably moved into a mounting position along the sides of the shoe receptacle a squeezing action will take place in the said last mentioned opposite side wall of the foot and this in turn causes remaining portions of this side wall of the foot to thereby be firmly, frictionally retained in physical surface to surface contact against an associated sidewall of the shoe receptacle.

The bow-shaped spring and the high friction nature of the material from which the foot is constructed thus enables an entire side portion of the foot to be frictionally engaged with an associated side of a shoe receptacle while the opposite side of the foot is retained against movement on the shoe receptacle due to a compressing force that is introduced into the spring when the foot is mounted on a shoe receptacle. Additionally, the engagement of the bow-spring with the metallic edge of an associated shoe provides one of the electrical contacts for a so-called hot-shoe connector.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the present invention may be had with the following detailed description when read in connection with the accompanying drawings in which:

FIG. 1 shows a plan view ofa friction foot attachment including a hollow body and the bow-shaped leaf spring mounted therein:

FIG. 2 shows an exploded view of the foot attachment: and

FIG. 3 shows how the parts of the friction foot attachment can be mounted in firm engagement with a shoe receptacle.

DESCRIPTION OF THE PREFERRED EMBODIMENT DETAILED DESCRIPTION Referring to FIGS. 1 and 2 in more detail there is shown a foot attachment 10 which is comprised of three major parts, namely, a hollow body or lower casing part 12, a bow-shaped leaf spring I4 and a top casing 16.

The top casing part 16 covers the upper open end of groove 80. i

An opening 84 is formed in the top casing 16 immedithe hollow body 12 of the foot attachment 10. The top casing part 16 may for example, be a casing portion which forms the base or bottom wall of any photographic accessory, such as a photographic flash unit 25. The top casing part 16 has two apertures 26, 28 therethrough that are in alignment with two similar apertures 30, 32 which extend through the top of the hollow body 12. A pair of screws 34, 36 pass through the aligned apertures 26, 28, and are connected in a tightened position at their lower end with associated apertured portions 30, 32 formed in body 12.

The top casing 16 thus provides a covering for the spring 14 which prevents the spring from moving in an upward direction out of the hollow body 12.

FIGS. 2 and 3 show thateach side of the foot attachment is provided with a top portion 38 and a runner 40 on one side and a similar top portion 42 and a runner 44 on its other side. The top portion 38 is separated from the associated runner 40 by a recessed side wall portion 46. Similarly,'the top portion 42 is separated from its associated runner 44 by a recessed side wall portion 48. Each runner 40, 44 extends outwardly of its respective associated side wallportions 46, 48. The runner 40 is shown so constructed that it does not extend as far away from the side surface 46 as the runner 44 extends away from the surface 48. This condition allows the foot to accommodate the various sized shoes that exist due to tolerance variations between manufacturers.

The arcuate portion 54 of the spring 14, which is shown in solid line form in FIG. 1, extends through a hole 56 forming an aperture in the side wall portion 46.

An outer wall portion of the bow-shaped leaf spring 14 is in contact with an inner wall surface 60 of the foot attachment 10.

A conductive tab 63 extends from the leaf spring 14 to which an electrical lead may be soldered. A center spring 64 comprises the other of the electrical contacts for the hot-shoe connection.

The spring 64 is a torsionally wound spring which is in the shape shown in FIGS. 1 & 2. The spring 64 has a coil spring portion 66, a torsion loop portion 68, a first end portion 76, and an opposite end portion 70. The first end portion 76 comprises a tab to which a second electrical lead may be soldered.

The lower surface of the coils of the coil spring portion 66 is supported by a wall 72 that forms the base of a recess 74 in the shoe attachment 10.

The torsion loop portion 68 of the spring 64 is positionally supported by grooves 78 and 80 formed in the upper face of the casing 12 adjacent the top portion 42 of the foot attachment 10. The looped end 76 extends upwardly through a slot 79 in the top casing 16.

The other end portion 70 of the spring 64 is also of a looped shaped configuration and is shown extending downwardly through and out ofa slot 82 that is formed in the base of the foot attachment 10.

The foot attachment 10 is mounted in its assembled condition on the bottom of the casing 16 of a photo flash unit 25. The lower surface of the top wall 16 reately above the coil portion 66 of the spring 64. A standard shutter cord 86 is providedwhich has a plug-in electrical connection 88 at one end for connection to the well known shutter contact terminals of a camera, not here shown. I

A second electric plug 92, which may be of the type known as a miniature phone plug is connected to the other end of the shutter cord 86. An opening 94 is formed in an end wall of the foot attachment 10 in order that the plug 92 maybe aligned with the lower portion of the coil spring 66 as shown in FIG. 1.

In FIG. 3 there is shown an attachment foot 10 secured to the lower surface 16 of a device such as an electronic flash unit 25. The assembly is shown in operative position relative to a complementary mounting shoe 50, shown in phantom=The mounting shoe 50 is of conventional construction and may be securely fastened to another structure such as a camera 52. The mounting shoe 50 includes a metallic frame member having the side edges folded to form a pair of re-entrant lips 58 and 61, respectively. The re-entrant lips 58 and 61, respectively'engage the runners 40 and 44 of the foot device 10. In that position, the runners 40 and 44 of the foot are frictionally gripped by the lip positions 58 and 61 of theshoe. Further, that portion 54 of the bow spring 14 which protrudes through the opening 56 is pressed inwardly by the edge of the lip 58. That compression ofthe spring 14 produces a lateral force on the foot 10 of sufficient magnitude to securely hold the foot rigidly to the shoe 50.

As may also be seen in FIG. 3, the looped end portion of the spring 64 protrudes through the slot 82, to en-. gage a metallic portion of the shoe 50. This arrangement allows the foot 10 to beused with a so-called hotshoe connector, one electrical contact being effected by the engagement of the loop .70 of the spring 64 with one of the contact areas of the hot shoe, the other electrical contact being effected through the engagement of the arcuate portion 54 of the spring 14 with the edge of the lip 58 of the shoe.

ln order to make the shoe universally usable, that is also operable with a shoe which is not of the hot-shoe type, means have been provided for accommodating a conventional PC connector cord 86. The PC cord has a miniature, two-terminal phone plug 92 at one end and a connector 88 at the otherend suitable for connection to the flash synchronization connector of the camera. When the foot 10 and the associated flash unit are to be used with a camera which does not have a hot-shoe connector, the engagement of two electrical contact means, i.e., the loop 70 of the spring 64 and the portion 54 of spring 14, with the metallic portions of a standard shoe would produce a short-circuit of the electrical terminals of the flash unit, rendering the flash unit inoper-- ative. Therefore, with such a camera, the insertion of the miniature phone plug 92 into opening 94 in the face of the shoe body 10 first causes the tip of the plug to lift the coiled portion 66 of the spring 64 toward the body of the flash unit. Such lifting of the coil 66 also causes the loop portion 70 to be retracted into the slot 82, thereby disengaging that electrical contact from the metallic surface of the standard shoe. As the plug 92 is fully seated in the opening 94, electrical contact is made between the tip contact of the plug 92 and the coiled portion of the spring 64. At the same time, electrical contact is established between the sleeve contact of the plug 92 and a curved end portion 96 of the spring 14.

Thus it may be seen that there has been provided in accordance with present invention, an improved attachment foot for photographic apparatus which may be used with either a conventional shoe or with a socalled hot-shoe, and which features a rigid mechanical coupling without the need for adjustable clamping devices.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination, an electrical plug and a mounting base for an electronic flash unit, said base having a retractable hot center contact, said base comprising a housing having a wall portion of insulative material, said contact comprising an electrically conductive spring mounted in said housing and having a coil portion and a hot contact portion connected to said coil portion, said'housing having first and second openings in said wall portion, said hot contact portion extending through said first opening in a first position and'being retracted inside said housing in a second position; said coil portion being positioned relative to said second opening such that insertion of said plug through said second opening to contact and displace said coil portion effects movement of said hot contact portion from said first position to said second position. v

2. The combination defined in claim 1 wherein the coil portion is a torsionally wound wire having one end thereof retained in a substantially fixed relationship with said housing.

3. The combination defined in claim 1 wherein the coil portion is a torsionally wound wire coil, said plug when inserted into said housing is positioned to contact and displace outer surface portions of said wire coils, to thereby introduce a torsional force in said spring while said hot contact portion is being moved to its said second position and wherein said torsional force introduced into said spring is effective to return said hot contact portion to its first position outwardly of said housing as said plug is moved out of contact with said coil portion of the spring. 

1. In combination, an electrical plug and a mounting base for an electronic flash unit, said base having a retractable hot center contact, said base comprising a housing having a wall portion of insulative material, said contact comprising an electrically conductive spring mounted in said housing and having a coil portion and a hot contact portion connected to said coil portion, said housing having first and second openings in said wall portion, said hot contact portion extending through said first opening in a first position and being retracted inside said housing in a second position; said coil portion being positioned relative to said second opening such that insertion of said plug through said second opening to contact and displace said coil portion effects movement of said hot contact portion from said first position to said second position.
 2. The combination defined in claim 1 wherein the coil portion is a torsionally wound wire having one end thereof retained in a substantially fixed relationship with said housing.
 3. The combination defined in claim 1 wherein the coil portion is a torsionally wound wire coil, said plug when inserted into said housing is positioned to contact and displace outer surface portions of said wire coils, to thereby introduce a torsional force in said spring while said hot contact portion is being moved to its said second position and wherein said torsional force introduced into said spring is effective to return said hot contact portion to its first position outwardly of said housing as said plug is moved out of contact with said coil portion of the spring. 